如何在使用vtkAppendPolyData时更改VTK中对象的颜色？

#include <vtkSmartPointer.h>
#include <vtkPolyData.h>
#include <vtkAppendPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkProperty.h>

int main()
{
    // 创建vtkPolyData对象
    vtkSmartPointer<vtkPolyData> polyData1 = vtkSmartPointer<vtkPolyData>::New();
    // 创建vtkAppendPolyData对象
    vtkSmartPointer<vtkAppendPolyData> appendPolyData = vtkSmartPointer<vtkAppendPolyData>::New();

    // 设置polyData1的颜色
    vtkSmartPointer<vtkPolyDataMapper> mapper1 = vtkSmartPointer<vtkPolyDataMapper>::New();
    mapper1->SetInputData(polyData1);
    vtkSmartPointer<vtkActor> actor1 = vtkSmartPointer<vtkActor>::New();
    actor1->SetMapper(mapper1);
    actor1->GetProperty()->SetColor(1.0, 0.0, 0.0); // 设置颜色为红色

    // 将polyData1添加到appendPolyData对象中
    appendPolyData->AddInputData(polyData1);

    // 创建vtkRenderer和vtkRenderWindow
    vtkSmartPointer<vtkRenderer> renderer = vtkSmartPointer<vtkRenderer>::New();
    vtkSmartPointer<vtkRenderWindow> renderWindow = vtkSmartPointer<vtkRenderWindow>::New();
    renderWindow->AddRenderer(renderer);

    // 将appendPolyData的输出连接到vtkPolyDataMapper和vtkActor
    vtkSmartPointer<vtkPolyDataMapper> mapper = vtkSmartPointer<vtkPolyDataMapper>::New();
    mapper->SetInputConnection(appendPolyData->GetOutputPort());
    vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
    actor->SetMapper(mapper);

    // 将actor添加到renderer中
    renderer->AddActor(actor);
    renderer->AddActor(actor1);

    // 设置渲染窗口的背景颜色
    renderer->SetBackground(1.0, 1.0, 1.0); // 设置背景颜色为白色

    // 创建vtkRenderWindowInteractor并启动事件循环
    vtkSmartPointer<vtkRenderWindowInteractor> interactor = vtkSmartPointer<vtkRenderWindowInteractor>::New();
    interactor->SetRenderWindow(renderWindow);
    renderWindow->Render();
    interactor->Start();

    return 0;
}